Struct optics::prelude::_Err

pub struct _Err;

Prism for Result::Err.

Trait Implementations

impl<T, E> AffineFold<Result<T, E>> for _Err

fn preview(&self, s: Result<T, E>) -> Result<E, Self::Error>

Retrieve the value targeted by an AffineFold.

impl<'a, T, E> AffineFoldMut<'a, Result<T, E>> for _Err

where E: 'a,

fn preview_mut(&self, s: &'a mut Result<T, E>) -> Result<&'a mut E, Self::Error>

Retrieve a mutable reference the value targeted by an AffineFold.

impl<'a, T, E> AffineFoldRef<'a, Result<T, E>> for _Err

where E: 'a,

fn preview_ref(&self, s: &'a Result<T, E>) -> Result<&'a E, Self::Error>

Retrieve a shared reference the value targeted by an AffineFold.

impl<T, E> AffineTraversal<Result<T, E>> for _Err

fn map(&self, s: &mut Result<T, E>, f: impl FnOnce(&mut E))

Restricted version for Setter::over. Custom implementation recommended.

fn set(&self, s: &mut T, a: Self::View)

Apply a setter. No Clone is needed, because this optics is affine.

impl Clone for _Err

fn clone(&self) -> _Err

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for _Err

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for _Err

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for _Err

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T, E> Optics<Result<T, E>> for _Err

type View = E

View type for this optics.

impl OpticsFallible for _Err

type Success = _Err

Success type for this optics.

type Error = _Err

Error type for this optics.

fn success_witness(&self) -> _Err

Get a lightweight witness for success.

fn map_fallible<S, F, E, G>(self, f: F, g: G) -> MapFallible<Self, F, G>

where Self: Sized, F: Fn(Self::Success) -> S, G: Fn(Self::Error) -> E,

Map the Success and Error type for this fallible optics.

fn map_success<S, F>(self, f: F) -> MapSuccess<Self, F>

where Self: Sized, F: Fn(Self::Success) -> S,

Map the Success type for this fallible optics.

fn map_error<E, G>(self, g: G) -> MapError<Self, G>

where Self: Sized, G: Fn(Self::Error) -> E,

Map the Error type for this fallible optics.

fn assert_infallible(self) -> MapFallibleTo<Self, Self::Success, Infallible>

where Self: Sized, Self::Error: Debug,

Assert that this optics should never fail (in practice). The resulting optics panics on error.

fn to_str_err(self) -> MapFallibleTo<Self, Self::Success, String>

where Self: Sized, Self::Error: Display,

Map the Error type to Box<str>.

impl Ord for _Err

fn cmp(&self, other: &_Err) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for _Err

fn eq(&self, other: &_Err) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for _Err

fn partial_cmp(&self, other: &_Err) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T, E> Review<Result<T, E>> for _Err

fn review(&self, a: E) -> Result<T, E>

Retrieve the value targeted by a review.

impl<T, E> Setter<Result<T, E>> for _Err

fn over(&self, s: &mut Result<T, E>, f: &mut dyn FnMut(&mut E))

Apply a setter as a modifier.

impl<T, E> Traversal<Result<T, E>> for _Err

fn traverse(&self, s: Result<T, E>, f: &mut dyn FnMut(E))

Evaluate the action from left to right on each element targeted by a Traversal.

fn fold<C>(&self, s: T, init: C, f: impl FnMut(&mut C, Self::View)) -> C

Fold every element targeted by this Traversal into a single result.

fn flatten(&self, s: T) -> Vec<Self::View>

Flatten the elements targeted by this Traversal into a Vec.

impl Copy for _Err

impl Eq for _Err

impl<T, E> Prism<Result<T, E>> for _Err

impl StructuralPartialEq for _Err